During 2004-2006 swine influenza virus surveillance, two strains of H3N8 influenza viruses were isolated from pigs in central China. Sequence and phylogenetic analyses of eight gene segments revealed that the two swine isolates were of equine origin and most closely related to European equine H3N8 influenza viruses from the early 1990s. Comparison of hemagglutinin (HA) amino acid sequences showed several important substitutions. One substitution caused the loss of a potential glycosylation site, and two substitutions, located at the cleavage site and adjacent to the receptor-binding pocket, respectively, had been reported previously in canine H3 HAs. This expansion of host range of equine H3N8 influenza viruses with mutations in the HA protein might raise the possibility of transmission of these viruses to humans.

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Melioidosis is a severe infectious disease caused by gram-negative, facultative intracellular pathogen Burkholderia pseudomallei ( B . pseudomallei ). Although cases are increasing reported from other parts of the world, it is an illness of tropical and subtropical climates primarily found in southeast Asia and northern Australia. Because of a 40% mortality rate, this life-threatening disease poses a public health risk in endemic area. Early detection of B . pseudomallei infection is vital for prognosis of a melioidosis patient. In this study, a novel isothermal recombinase polymerase amplification combined with lateral flow dipstick (LF-RPA) assay was established for rapid detection of B . pseudomallei . A set of primer-probe targeting orf 2 gene within the putative type III secretion system (T3SS) cluster genes was generated and parameters for the LF-RPA assay were optimized. Result can be easy visualized in 30 minutes with the limit of detection (LOD) as low as 20 femtogram (fg) (ca. 25.6 copies) of B . pseudomallei genomic DNA without a specific equipment. The assay is highly specific as no cross amplification was observed with Burkholderia mallei , members of the Burkholderia cepacia -complex and 35 non- B . pseudomallei bacteria species. Moreover, isolates from patients in Hainan ( N = 19), Guangdong ( N = 1), Guangxi ( N = 3) province of China as well as in Australia ( N = 3) and Thailand ( N = 1) were retrospectively confirmed by the newly developed method. LODs for B . pseudomallei -spiked soil and blood samples were 2.1×10 3 CFU/g and 4.2×10 3 CFU/ml respectively. The sensitivity of the LF-RPA assay was comparable to TaqMan Real-Time PCR (TaqMan PCR). In addition, the LF-RPA assay exhibited a better tolerance to inhibitors in blood than TaqMan PCR. Our results showed that the LF-RPA assay is an alternative to existing PCR-based methods for detection of B . pseudomallei with a potentiality of early accurate diagnosis of melioidosis at point of care or in-field use.

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The results from this study suggest that this gene and the protease inhibitor protein encoded may offer an alternative method to control aphids in the future.